Joint for telephone-transmitter arms.



. Patented mm2; |9025 i c. T. MASQN.y i JOINT FUR TELPHD'NEV TRANSMITTER ARMS.

(Application med June 3, 4190k.)

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me Nonms PETERS co, Pnoourrm.. wnsumsf "UNITED y STATES IDATENT OFFICE.

CHARLES THOMAS `MASON, OF SUMTER, SOUTH CAROLINA.

JOINT FOR TELEPHONE-TRANSMITTER ARMS.

SPECIFICATION forming part of Letters Patent No. 714,813, dated December 2, 1902.

Application iiled June 3,1902.

.T a/ZZ whom it may concern/.r

Beit knownthat I, CHARLES THOMAS MA- SON, a citizen of the United States, residing at Sumter, in the county of Sumter and State of South Carolina, have invented certain new and useful Improvements in Joints for Telephone-Transmitter Arms; and I do hereby de clare the following to be a full, clear, and exact description of the invention, such as will `enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of thisspeciiication.

This invention relates to` joints for telephone-transmitter arms, meaning thereby the arm by which the transmitter and mouth- `piece are adjustably supported on the base.

The object. of the `invention is to form a joint the friction of which may be adjusted by a thumb-nut, havingthe advantage over `existing joints that a bearing-surface does not have to be ground and finished upon the `arm or the ears ofthe base. The bearings of my joint may be separately formed or turned out by automatic machinery from steel, avoiding the grinding and finishing of bearing-surfaces on the cast-iron parts.

A further object of the invention is to provide a cheaper and more durable and effl-` cient friction-joint than has heretofore been constructed which may be adjusted without the use of tools.

The invention involves a cone bearing which, however, is quite different from an existing joint in which the arm is pivoted upon cone-pointed screws held by bindingnuts, which construction requires the use of a Wrench to loosen the nuts and a screw- Referring specificallyT to the drawings, t3 indicates the base, and 6 the ears thereon, be-

tween whichthe arm 7 is pivoted. The arm may be solid or hollow, as desired.

, `shown the same hollow.

I have Serial No. 110,088. (No model.)

The pivot-pin is indicated at 8, having at one end a head fitting snugly through the hole in one of the ears. The head has a small pin 8, which projectsinto a notch 6b in the ear to prevent the pin turning when the parts are assembled. A sleeve 8b slides loosely on the pin; and this sleeve and the head of' the pin have bearing-cones 8C, which frictionally engage corresponding countersunk holes in the arm. The sleeve 8b has also a pin. 8d in a notch 6b to prevent the sleeve from turning. The outer end of the pin is threaded to receive a thumb-nut 9, by which the friction contact is adjusted. It will be understood that this contact is sufficient to retain the arm in the position in which it is set, yet not so great as to preventits movement. The thumbnut bears against the cone-sleeve 8b, and movement thereof aifects the friction in an obvious manner. The head of the pin is slightly spread or expanded, as at 8e', so that it may not be drawn through the ear.

In the modification shown in Fig. 3 the conesleeve is recessed to form a seat for .a spring l0, coiled around the pin and bearing in compression against the thumb-nut. This provides a uniform tension at all times. If desired, the spring may be removed to effect the thumb-nut tension.

It will be seen that the sides of the arm do not contact with the ears. Therefore the surfaces can be left unfinished, whereby the expense of grinding incident to Athe common joint is avoided. 'The arm is supported by the cone-bearings, and anynecessary adjustment may be effected without theuse of any tools. Furthermore, the bearing-cones cannotturn and will not work loose.

What I claim as my invention is- 1. Inajointfortelephone-transmitterarms, the combination with a base and the arm, of a pivot-pin supported by the base and extending through the arm and having adjustable bearing-cones between which the arm is held in friction, out of contact with the base.

2. In a joint for telephone-transmitter arms, the combination with a support and the arm, of a pivot-pin carried by the support and having adjustable, spring-supported, bearingcones thereon between which the arm is held in friction.

3. In a joint for telephone-transmitter arms,

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the combination with the base and ears, and arm having countersinks to receive the cones the arm, of a pivot-pin extending through the ears and arm, bearing-cones on the pin, one of which is slidable, between which the arm is held in friction, and a binding-nut on the pin adjacent the sliding cone, to adjust the friction.

4. Inajoint for telephone-transmitter arms, the combination with the base, and a thread- 1o ed pivot-pin supported thereby having a conehead, of a cone-sleeve siidable on the pin, an

and heid in friction therebetween, out of con- In testimony whereof I affix my signature in presence of two witnesses.

CHARLES THOMAS MASON.

Witnesses: y

C. G. ROWLAND, F. C. MANNING. 

